1. Field of the Invention
The invention concerns a printing apparatus of the type having an inkjet printing device with an ink cartridge plugged into a cartridge carrier, and a control unit that controls the printing. The cartridge carrier is mounted on a sled that is moved back and forth during the printing. The sled can be controlled into a predetermined position to exchange the ink cartridge. The inserted ink cartridge is locked and can be unlocked and ejected via a mechanism installed on the side of the cartridge carrier. The printing apparatus is suitable for 1-inch receipt printers and is used in franking and addressing machines, and in other printing mail processing apparatuses.
2. Description of the Prior Art
An arrangement for exchanging ink cartridges is known from German Patent Application DE 102007060733 A1. This printing apparatus has a transport device for flat goods, a contact pressure device and a printing module, wherein the transport device is stationary in the printing device relative to a contact pressure device that presses the mail piece onto a transport belt of the transport device. The transport belt acts in the transport region with a predetermined stiction on a portion of the surface of the mail piece that has not been inprinted but is situated near to the region to be printed. An exchange position for ink cartridges is located before the transport region, on the front side of the printing device, or above the transport region of the transport device, which is designed to allow such exchange.
The printing module has a print carriage with two compartments for insertion of ink cartridges. Upon insertion, the ink cartridges have a bulge directed forward that includes an ink reservoir. The print carriage of the printing module has a respective opening for insertion of the ink cartridges, which opening is limited laterally by a right-side plate and left-side plate and at the floor by a shaped carrier part, as well as to the rear by a contact panel of the contacting and control electronics. The shaped carrier part is comprised of two halves that are offset relative to one another. A locking lever is attached to the right-side plate and left-side plate so as to be rotatable. The print head of each of the ink cartridges that are arranged offset relative to one another is situated in a printing position during the printing. The print carriage is designed accordingly in order to be moved forward—transverse to the mail piece transport direction—starting from the printing position into an exchange position. The exchange position lies at the front side of the printing device or above the transport region of a transport device that is thereby designed accordingly. The transport region is situated at the front side of the printing device, and the printing region adjoins this to the rear.
From German Patent Application DE 102008033052 A1, an arrangement for exchanging ink cartridges is known that has a print carriage with a shaft-like receptacle for ink cartridges. The contact panel of the contacting and control electronics on the back side of each shaft has a number of counter-contacts. The counter-contacts are arranged so as to be adjustable and are mechanically coupled with the latch of a locking mechanism so that the counter-contacts are distanced from the ink cartridge simultaneously with the unlocking of the ink cartridge, and the counter-contacts are contacted with the contact panel and a chip on the ink cartridge with the locking of the ink cartridge. The latch serves as a locking lever and interacts with a locking projection on the edge between the narrow top side and the narrow back side of the ink cartridge, wherein the locking projection is matched to the contour of the latch.
In the European Patent EP 1 880 857 B1, an arrangement for exchanging ink printing modules was proposed, wherein what are designated with the latter term are ink cartridges that can be inserted directly into a receptacle of the pivot device. The arrangement has latches to lock the ink cartridges and, per ink cartridge, a draw hook mechanically connected with a retaining spring as well as a guide lever. After the exchange, the retaining springs pull the draw hooks back into a starting position. This device attached to the ink cartridge receptacle for the exchange of said ink cartridges is materially intensive and can lead to a contamination problem given a disadvantageous manual operation of the draw hooks, because the lower trailing edge of the nozzle surface of the ink cartridge rests on an elastic part that should prevent contact of the counterpart with the contact panel, but the clearance is so small that contact of the counterpart to the contact panel due to contamination therebetween cannot be precluded. The contact problem results from the fact that the clearance is small and the elastic part and the contacts can be contaminated with ink upon removal of the ink cartridge, such ink having accumulated on the lower trailing edge during the printing. The draw hook and the elaborate mechanism of the aforementioned prior art are disadvantageous to an easy exchange of the ink cartridges.
In German Patent DE 10 2008 030 530 B4, an ink cartridge receptacle is disclosed that has neither draw hooks nor the elaborate locking mechanism of the aforementioned prior art, and given which the contamination problem is remedied. The ink cartridge has been modified by a guide pin that is attached to the bulge or between bulge and head of the ink cartridge and projects past the flat side wall only on one side for the purpose of guiding the ink cartridge. While inserting the ink cartridge, the guide pin slides along into a connecting guide member in a wall of an ink cartridge receptacle. Given an inserted ink cartridge, a leaf spring is pre-tensioned in each cavity of the cartridge carrier (which cavity is provided for an ink cartridge) of the ink cartridge receptacle, and the exchange of the ink cartridge is assisted by spring force when the locking projection and the locking element of the ink cartridge carrier disengage per manual pressure on the ink cartridge and the ink cartridge is pivoted on an axis traveling nearly parallel to the guide pin in order to unlock the ink cartridge, wherein the clearance of the lower trailing edge of the ink cartridge from the contact panel of the cartridge carrier is precisely determined by the course of the connecting guide member.
A franking machine is known from German Utility Patent DE 202012005904 U1 that has an ink printing device onto which a flat good is pressed by a contact pressure device. The ink printing device includes exchangeable ink cartridges. Instead of a leaf spring, in the ink cartridge receptacle a compression spring is used via whose spring force the exchange of the ink cartridge is assisted after the locking projection and the locking element of the ink cartridge carrier have been disengaged per manual pressure. An advantage of the manual handling is that the ink cartridge is held in the hand after the contacts are released, and therefore the ink cartridge does not spring out of the cartridge carrier far enough so that the ink cartridge reaches the opened hatch of the franking machine.
A commercially available franking machine Mymail® from Francotyp Postalia GmbH (which has a very small structural shape) provides sufficient space for neither a leaf spring nor a compression spring in the cavity of the cartridge carrier for accommodation of the ink cartridge; see EP 1127701 B1. Given an activated franking machine, at any point in time before printing a cover can be opened, a release can be unlocked and the ink cartridges can be removed. During the printing, the ink cartridge moves and therefore cannot be exchanged. The cartridge carrier (formed from two side parts in a manner known per se) is mounted on a sled in a known manner, which sled is arranged so as to move by sliding on a guide rod. The outside of the right-side part is designated in the following as what is known as the sled side, since this is provided for mounting of the cartridge carrier on the sled. The outside of the left-side part is designated as what is known as the connection side since this is provided for connection of a ribbon cable for conductive connection of the electrical terminal contacts of the ink cartridge with the control unit. The installed cartridge carrier has in a known manner an upward opening for sliding the ink cartridge into a cavity, and a narrow wall bent outward from the outer edge of the left-side part and right-side part. Given a small structural shape of the cartridge carrier with connecting guide member, a compression spring would be unsuitable in order to supply a force that would be necessary to convey the ink cartridge out of the cavity. The compression spring would need to be realized so as to be strongly compressible during the insertion of the ink cartridge into the cavity of the cartridge carrier of the ink cartridge receptacle, which requires an additional structural space. It is furthermore disadvantageous that the ink cartridge can also be manually exchanged when the cartridge carrier is rotated into a sealing position for the ink cartridge. The print head could be damaged if, given manual operation, the ink cartridge is pushed in too far in order to press the locking edge of the ink cartridge past an edge at the opening of the cartridge carrier. The print head of the ink cartridge could thereby be damaged given a contact with the service station. All of this is disadvantageous given a manual handling of the ink cartridges.